13.6.2.12 Exceptions

New in version 2.1.

The DOM Level 2 recommendation defines a single exception, DOMException, and a number of constants that allow applications to determine what sort of error occurred. DOMException instances carry a code attribute that provides the appropriate value for the specific exception.

The Python DOM interface provides the constants, but also expands the set of exceptions so that a specific exception exists for each of the exception codes defined by the DOM. The implementations must raise the appropriate specific exception, each of which carries the appropriate value for the code attribute.

exception DOMException: Base exception class used for all specific DOM exceptions. This exception class cannot be directly instantiated.

exception DomstringSizeErr: Raised when a specified range of text does not fit into a string. This is not known to be used in the Python DOM implementations, but may be received from DOM implementations not written in Python.

exception HierarchyRequestErr: Raised when an attempt is made to insert a node where the node type is not allowed.

exception IndexSizeErr: Raised when an index or size parameter to a method is negative or exceeds the allowed values.

exception InuseAttributeErr: Raised when an attempt is made to insert an Attr node that is already present elsewhere in the document.

exception InvalidAccessErr: Raised if a parameter or an operation is not supported on the underlying object.

exception InvalidCharacterErr: This exception is raised when a string parameter contains a character that is not permitted in the context it's being used in by the XML 1.0 recommendation. For example, attempting to create an Element node with a space in the element type name will cause this error to be raised.

exception InvalidModificationErr: Raised when an attempt is made to modify the type of a node.

exception InvalidStateErr: Raised when an attempt is made to use an object that is not or is no longer usable.

exception NamespaceErr: If an attempt is made to change any object in a way that is not permitted with regard to the Namespaces in XML recommendation, this exception is raised.

exception NotFoundErr: Exception when a node does not exist in the referenced context. For example, NamedNodeMap.removeNamedItem() will raise this if the node passed in does not exist in the map.

exception NotSupportedErr: Raised when the implementation does not support the requested type of object or operation.

exception NoDataAllowedErr: This is raised if data is specified for a node which does not support data.

exception NoModificationAllowedErr: Raised on attempts to modify an object where modifications are not allowed (such as for read-only nodes).

exception SyntaxErr: Raised when an invalid or illegal string is specified.

exception WrongDocumentErr: Raised when a node is inserted in a different document than it currently belongs to, and the implementation does not support migrating the node from one document to the other.

The exception codes defined in the DOM recommendation map to the exceptions described above according to this table:

Constant Exception

DOMSTRING_SIZE_ERR DomstringSizeErr
HIERARCHY_REQUEST_ERR HierarchyRequestErr
INDEX_SIZE_ERR IndexSizeErr
INUSE_ATTRIBUTE_ERR InuseAttributeErr
INVALID_ACCESS_ERR InvalidAccessErr
INVALID_CHARACTER_ERR InvalidCharacterErr
INVALID_MODIFICATION_ERR InvalidModificationErr
INVALID_STATE_ERR InvalidStateErr
NAMESPACE_ERR NamespaceErr
NOT_FOUND_ERR NotFoundErr
NOT_SUPPORTED_ERR NotSupportedErr
NO_DATA_ALLOWED_ERR NoDataAllowedErr
NO_MODIFICATION_ALLOWED_ERR NoModificationAllowedErr
SYNTAX_ERR SyntaxErr
WRONG_DOCUMENT_ERR WrongDocumentErr

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